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https://www.readbyqxmd.com/read/28738291/inflammation-responsive-self-regulated-drug-release-from-ultrathin-hydrogel-coating
#1
Min He, Qian Wang, Zhenqiang Shi, Yi Xie, Weifeng Zhao, Changsheng Zhao
Heterotopic ossification(HO) is a potential severe complication after many biomaterial implanting surgeries, and the inflammation environment caused by the implanting-associated infections is considered as the main nosogenesis. Herein, an inflammation-responsive drug release system was designed by chemically conjugating indometacin (via ester group) onto hydrogel coating to realize local self-regulated drug release to prevent HO. In our strategy, poly(3-mercaptopropyl)trimethoxysilane-co-acrylic acrylate and polyvinyl alcohol (providing anchoring sites for drug molecules) were firstly synthesized and functionalized with ene-groups, then a hydrogel layer was formed and covalently attached onto thiol-modified substrate via thiol-ene click chemistry, followed by grafting indometacin...
July 18, 2017: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/28737926/geometric-shape-regulation-and-non-covalent-synthesis-of-one-dimensional-organic-luminescent-nano-micro-materials
#2
Xiaoxian Song, Zuolun Zhang, Shou-Feng Zhang, Jinbei Wei, Kaiqi Ye, Yu Liu, Todd B Marder, Yue Wang
Non-covalent synthesis of one-dimensional (1D) organic nano/micro-materials with controllable geometric shapes or morphologies and special luminescent/electronic properties is one of the greatest challenges in modern chemistry and material science. Control of non-covalent interactions is fundamental for realizing desired 1D structures and crucial for understanding the functions of these interactions. Here, a series of thiophene-fused phenazines composed of a halogen-substituted π-conjugated plate and a pair of flexible side chains is presented, which displays halogen-dependent 1D self-assemblies...
July 24, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28737907/in-situ-solid-gas-reactivity-of-nanoscaled-metal-borides-from-molten-salt-synthesis
#3
Guillaume Gouget, Damien P Debecker, Ara Kim, Giorgia Olivieri, Jean-Jacques Gallet, Fabrice Bournel, Cyril Thomas, Ovidiu Ersen, Simona Moldovan, Clément Sanchez, Sophie Carenco, David Portehault
Metal borides have mostly been studied as bulk materials. The nanoscale provides new opportunities to investigate the properties of these materials, e.g., nanoscale hardening and surface reactivity. Metal borides are often considered stable solids because of their covalent character, but little is known on their behavior under a reactive atmosphere, especially reductive gases. We use molten salt synthesis at 750 °C to provide cobalt monoboride (CoB) nanocrystals embedded in an amorphous layer of cobalt(II) and partially oxidized boron as a model platform to study morphological, chemical, and structural evolutions of the boride and the superficial layer exposed to argon, dihydrogen (H2), and a mixture of H2 and carbon dioxide (CO2) through a multiscale in situ approach: environmental transmission electron microscopy, synchrotron-based near-ambient-pressure X-ray photoelectron spectroscopy, and near-edge X-ray absorption spectroscopy...
July 24, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28737891/dynamic-chemistry-based-sensing-a-molecular-system-for-detection-of-saccharide-formaldehyde-and-silver-ion
#4
Xingmao Chang, Zhaolong Wang, Yanyu Qi, Rui Kang, Xinwen Cui, Congdi Shang, Kaiqiang Liu, Yu Fang
Development of artificial complex molecular systems is of great importance in understanding complexity in natural processes and for achieving new functionalities. One of the strategies is to create them via optimized utilization of noncovalent interactions and dynamic covalent bonds. We report here on a new complex molecular system, which was constructed by integrating the multiple interactions containing dynamic covalent interaction between 1,2-diol and boronic acid, coordination interaction between silver ion and pyridyl, and an easy accessible reaction between secondary amine and formaldehyde...
July 24, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28737762/mechanism-of-host-substrate-acetylation-by-a-yopj-family-effector
#5
Zhi-Min Zhang, Ka-Wai Ma, Linfeng Gao, Zhenquan Hu, Simon Schwizer, Wenbo Ma, Jikui Song
The Yersinia outer protein J (YopJ) family of bacterial effectors depends on a novel acetyltransferase domain to acetylate signalling proteins from plant and animal hosts. However, the underlying mechanism is unclear. Here, we report the crystal structures of PopP2, a YopJ effector produced by the plant pathogen Ralstonia solanacearum, in complex with inositol hexaphosphate (InsP6), acetyl-coenzyme A (AcCoA) and/or substrate Resistance to Ralstonia solanacearum 1 (RRS1-R)WRKY. PopP2 recognizes the WRKYGQK motif of RRS1-RWRKY to position a targeted lysine in the active site for acetylation...
July 24, 2017: Nature Plants
https://www.readbyqxmd.com/read/28737377/carbon-dot-based-naphthalimide-coupled-fret-pair-for-highly-selective-ratiometric-detection-of-thioredoxin-reductase-and-cancer-screening
#6
Jagpreet Singh Sidhu, Ashutosh Singh, Neha Garg, Narinder Singh
The Fluorescence resonance energy transfer (FRET) mechanism has been established between the carbon dots (CDs) and naphthalimide to monitor the activity of thioredoxin reductase (TrxR), which is often overexpressed in many cancer cells. The naphthalimide moiety was covalently attached to the surface of CDs through a disulfide linkage. In the normal cell conditions (when devoid of high concentrations of TrxR), the CDs act as an energy donor and naphthalimide acts as an acceptor, which establishes the FRET pair as interpreted from the emission at λem =565 nm, when excited at λex =360 nm...
July 24, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28737039/effect-of-solvent-quality-on-laminar-slip-flow-penetration-of-poly-n-isopropylacrylamide-films-with-an-exploration-of-the-mass-transport-mechanism
#7
Huan Wang, Jeanne E Pemberton
The effect of solvent quality on the slip flow penetration of polymer films was evaluated by monitoring small-molecule mass transport under varying laminar flow rates using Förster resonance energy transfer in combination with total internal reflectance fluorescence microscopy (FRET-TIRFM). For thin films of poly(N-isopropylacrylamide) (pNIPAM), solvents with solvent quality ranging from good to poor were studied. The solvents used were composed of varying mole ratios of methanol and water in order to take advantage of the unique cononsolvency phenomenon of pNIPAM such that differences in the physicochemical properties of these solvents were insignificant for fluorescence detection...
July 24, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28736985/conducting-polymers-crosslinked-with-sulfur-as-cathode-materials-for-high-rate-ultralong-life-lithium-sulfur-batteries
#8
Ligui Li, Shuaibo Zeng, Lihong Xie, Dengke Zhao, Nan Wang, Shaowei Chen
Low electrical conductivity and lack of chemical confinement are two major factors that limit the rate performance and cycling stability of cathode materials in lithium-sulfur (Li-S) batteries. Herein, sulfur is copolymerized with poly(m-aminothiophenol) (PMAT) nanoplates via inverse vulcanization, leading to a highly crosslinked copolymer cp(S-PMAT) in which about 80 wt% of the feeding sulfur is chemically bonded with the thiol groups of PMAT. The cp(S-PMAT)/C based cathode exhibits a high discharge capacity of 1240 mAh g-1 at 0...
July 23, 2017: ChemSusChem
https://www.readbyqxmd.com/read/28736857/non-covalent-assembly-method-that-simultaneously-endows-a-liposome-surface-with-targeting-ligands-protective-peg-chains-and-deep-red-fluorescence-reporter-groups
#9
Scott K Shaw, Wenqi Liu, Seamus Brennan, Maria Betancourt-Mendiola, Bradley D Smith
A new self-assembly method is used to rapidly functionalize the surface of liposomes without perturbing the membrane integrity or causing leakage of the aqueous contents. The key molecule is a cholesterol-squaraine-PEG conjugate with three important structural elements: a cholesterol membrane anchor, a fluorescent squaraine docking station that allows rapid and high-affinity macrocycle threading, and a long PEG-2000 chain to provide steric shielding of the decorated liposome. The two-step method involves spontaneous insertion of the conjugate into the outer leaflet of pre-formed liposomes followed by squaraine threading with a tetralactam macrocycle that has appended targeting ligands...
July 23, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28736333/synthesis-and-characterization-of-a-multifunctional-gold-doxorubicin-nanoparticle-system-for-ph-triggered-intracellular-drug-release
#10
Ganesh V Khutale, Alan Casey
A nanoparticle drug carrier system has been developed to alter the cellular uptake and chemotherapeutic performance of an available chemotherapeutic drug. The system comprises of a multifunctional gold nanoparticle based drug delivery system (Au-PEG-PAMAM-DOX) as a novel platform for intracellular delivery of doxorubicin (DOX). Spherical gold nanoparticles were synthesized by a gold chloride reduction, stabilized with thiolated polyethylene glycol (PEG) and then covalently coupled with a polyamidoamine (PAMAM) G4 dendrimer...
July 20, 2017: European Journal of Pharmaceutics and Biopharmaceutics
https://www.readbyqxmd.com/read/28735540/the-n%C3%A2-%C3%AF-interaction
#11
Robert W Newberry, Ronald T Raines
The carbonyl group holds a prominent position in chemistry and biology not only because it allows diverse transformations but also because it supports key intermolecular interactions, including hydrogen bonding. More recently, carbonyl groups have been found to interact with a variety of nucleophiles, including other carbonyl groups, in what we have termed an n→π* interaction. In an n→π* interaction, a nucleophile donates lone-pair (n) electron density into the empty π* orbital of a nearby carbonyl group...
July 23, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28735148/mechanically-competent-and-cytocompatible-polycaprolactone-borophosphosilicate-hybrid-biomaterials
#12
Dibakar Mondal, S Jeffrey Dixon, Kibret Mequanint, Amin S Rizkalla
Organic-inorganic class II hybrid materials have domain sizes at the molecular level and chemical bonding between the organic and inorganic phases. We have previously reported the synthesis of class II hybrid biomaterials from alkoxysilane-functionalized polycaprolactone (PCL) and borophosphosilicate (B2O3-P2O5-SiO2) glass (BPSG) through a non-aqueous sol-gel process. In the present study, the mechanical properties and degradability of these PCL/BPSG hybrid biomaterials were studied and compared to those of their conventional composite counterparts...
July 5, 2017: Journal of the Mechanical Behavior of Biomedical Materials
https://www.readbyqxmd.com/read/28735093/stable-isotope-labeling-by-fatty-acids-in-cell-culture-silfac-coupled-with-isotope-pattern-dependent-mass-spectrometry-for-global-screening-of-lipid-hydroperoxide-mediated-protein-modifications
#13
Ryo Takahashi, Shuhei Fujioka, Tomoyuki Oe, Seon Hwa Lee
Lipid hydroperoxide-mediated modifications of proteins are receiving increasing attention because of their possible involvement in various degenerative diseases. These biological effects are attributed to the ability of lipid peroxidation-derived aldehydes to react with the nucleophilic sites of proteins. Here we describe a methodology involving metabolic labeling coupled with mass spectrometry-based proteomic analysis that enables global screening of lipid hydroperoxide-mediated protein modifications in a cell system...
July 19, 2017: Journal of Proteomics
https://www.readbyqxmd.com/read/28735029/peptide-modification-of-polyimide-insulated-microwires-towards-improved-biocompatibility-through-reduced-glial-scarring
#14
Sangita Sridar, Matthew A Churchward, Vivian K Mushahwar, Kathryn G Todd, Anastasia L Elias
The goal of this study is to improve the integration of implanted microdevices with tissue in the central nervous system (CNS). The long-term utility of neuroprosthetic devices implanted in the CNS is affected by the formation of a scar by resident glial cells (astrocytes and microglia), limiting the viability and functional stability of the devices. Reduction in the proliferation of glial cells is expected to enhance the biocompatibility of devices. We demonstrate the modification of polyimide-insulated microelectrodes with a bioactive peptide KHIFSDDSSE...
July 19, 2017: Acta Biomaterialia
https://www.readbyqxmd.com/read/28735002/immobilization-of-%C3%AE-galactosidase-on-surface-modified-cobalt-multiwalled-carbon-nanotube-nanocomposite-improves-enzyme-stability-and-resistance-to-inhibitor
#15
Maryam Khan, Qayyum Husain, Rani Bushra
The present study aimed to work out a high yield procedure for immobilization of Aspergillus oryzae β-galactosidase on polyaniline cobalt multiwalled carbon nanotubes nanocomposite (PANI/Co/MWCNTNC) by physical adsorption and covalent attachment via glutaraldehyde. The binding was confirmed by scanning and transmission electron microscopy along with Fourier transform-infrared spectroscopy. The immobilization yields obtained for adsorbed and cross-linked enzymes were 93% and 97%, respectively. The covalently immobilized enzyme was remarkably more stable at extremes of pH and temperature compared to native and adsorbed enzymes...
July 19, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28734934/analysis-of-rna-protein-interactions-in-vertebrate-embryos-using-uv-crosslinking-approaches
#16
Vladimir Despic, Mario Dejung, Falk Butter, Karla M Neugebauer
A decade ago, we believed that at least 300 RNA binding proteins (RBPs) were encoded in our genomes based on annotations of known or predicted RNA binding domains. Deciphering the roles of those RBPs in regulated gene expression was a vast frontier awaiting exploration. Since then, the field has developed a number of key tools that navigate the landscape of cellular RNA. These rely principally on UV crosslinking to create covalent bonds between RBPs and target RNAs in vivo, revealing not only target identities but also local binding sites upon RNA-Seq...
July 19, 2017: Methods: a Companion to Methods in Enzymology
https://www.readbyqxmd.com/read/28734478/ph-dependent-membrane-interactions-of-the-histidine-rich-cell-penetrating-peptide-lah4-l1
#17
Justine Wolf, Christopher Aisenbrey, Nicole Harmouche, Jesus Raya, Philippe Bertani, Natalia Voievoda, Regine Süss, Burkhard Bechinger
The histidine-rich designer peptide LAH4-L1 exhibits antimicrobial and potent cell-penetrating activities for a wide variety of cargo including nucleic acids, polypeptides, adeno-associated viruses, and nanodots. The non-covalent complexes formed between the peptide and cargo enter the cell via an endosomal pathway where the pH changes from neutral to acidic. Here, we investigated the membrane interactions of the peptide with phospholipid bilayers and its membrane topology using static solid-state NMR spectroscopy...
July 19, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28734285/extension-of-the-d3-dispersion-coefficient-model
#18
Eike Caldeweyher, Christoph Bannwarth, Stefan Grimme
A new model, termed D4, for the efficient computation of molecular dipole-dipole dispersion coefficients is presented. As in the related, well established D3 scheme, these are obtained as a sum of atom-in-molecule dispersion coefficients over atom pairs. Both models make use of dynamic polarizabilities obtained from first-principles time-dependent density functional theory calculations for atoms in different chemical environments employing fractional atomic coordination numbers for interpolation. Different from the D3 model, the coefficients are obtained on-the-fly by numerical Casimir-Polder integration of the dynamic, atomic polarizabilities α(iω)...
July 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28733410/radioactive-labeling-and-fractionation-of-fission-yeast-walls
#19
Pilar Pérez, Juan C Ribas
Fungal cells contain an essential structure external to the cell, made of polysaccharides and proteins, termed the cell wall. Polysaccharides represent ∼96% of the cell wall on a dry-weight basis. They are complex insoluble polymers connected to each other by covalent linkages and hydrogen bonds with specific localizations in the cell wall and septum. Fission yeast contains three β-glucans (a major branched β(1,3)-glucan, a minor linear β(1,3)-glucan, and a minor branched β(1,6)-glucan), two α-glucans (a major α(1,3)-glucan and a minor α(1,4)-glucan), and a minor amount of galactomannan-linked glycoproteins...
July 21, 2017: Cold Spring Harbor Protocols
https://www.readbyqxmd.com/read/28733082/effects-of-novel-triple-stage-antimalarial-ionic-liquids-on-lipid-membrane-models
#20
Ricardo Ferraz, Marina Pinheiro, Ana Gomes, Cátia Teixeira, Cristina Prudêncio, Salette Reis, Paula Gomes
Primaquine-based ionic liquids, obtained by acid-base reaction between parent primaquine and cinnamic acids, were recently found as triple-stage antimalarial hits. These ionic compounds displayed significant activity against both liver- and blood-stage Plasmodium parasites, as well as against stage V P. falciparum parasites. Remarkably, blood-stage activity of the ionic liquids against both chloroquine-sensitive (3D7) and resistant (Dd2) P. falciparum strains was clearly superior to those of the respective covalent (amide) analogues and of parent primaquine...
July 3, 2017: Bioorganic & Medicinal Chemistry Letters
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